There are known solid-state imaging devices using CCD, which can transfer electric charges bi-directionally in a vertical direction (e.g., cf. Patent Literature 1). In the solid-state imaging device described in Patent Literature 1, three gates are provided per pixel and three-phase voltages of different phases are applied respectively to the three gates. This allows an electric charge generated in response to incidence of light in an imaging area to be moved bi-directionally in the vertical direction. The solid-state imaging device described in Patent Literature 1 is provided with a horizontal shift register for horizontally transferring the electric charge vertically transferred from the imaging area. The electric charge transferred by the horizontal shift register is converted into a voltage signal by a readout amplifier to be read out to the outside of the solid-state imaging device. In the solid-state imaging device described in Patent Literature 1, a plurality of readout amplifiers are provided horizontally in juxtaposition to implement multi-port output, thus realizing speed-up of readout of electric charges. However, when the horizontal shift register is used as in the technology described in Patent Literature 1, there is a limit to the speed-up of readout of electric charges, even with the implementation of multi-port output. There are recent demands for further speed-up of readout of electric charges.
A known technology for further speed-up of readout of electric charges is the technology of providing one output amplifier per two adjacent columns, out of pixel columns arranged in a two-dimensional array, and reading out electric charges with use of this output amplifier (e.g., cf. Patent Literature 2). In the solid-state imaging device described in Patent Literature 2, six-phase drive voltages are applied in an imaging area and a buffer area. The drive voltages control depths of potentials in a semiconductor substrate to transfer the electric charges from the imaging area to the buffer area, and the electric charges thus transferred are read out as voltage signals by the amplifier.